Low α2-macroglobulin, impaired fibrinolysis up risk of asthma exacerbation
Lower plasma levels of α2-macroglobulin and impaired fibrinolysis appear to increase the risk of asthma exacerbations, a new study has shown.
In the study sample of 157 patients with asthma, 198 severe asthma exacerbations were recorded, corresponding to 64 events per year. These were observed in 34 percent (n=53) of the patients, of whom 33 had at least three complication events.
Those who experienced exacerbations were significantly older (p=0.004), had longer asthma duration (p=0.006) and worse asthma control (p=0.02). Those with exacerbations also showed significantly lower forced expiratory volumes in 1 second (p=0.01) compared with controls.
Interestingly, in those who experienced at least one exacerbation, clot lysis time (CLT) was significantly longer (p=0.038) and α2-macroglobulin levels were significantly lower (p=0.04) after controlling for potential confounders.
Even in moderate and severe asthmatics (n=47), at least one case of asthma exacerbation was association with significantly higher CLT (p=0.002) and lower α2-macroglobulin (p=0.04).
In multiple logistic regression analysis, asthma duration (odds ratio [OR], 1.037; 95 percent CI, 1.011 to 1.065; p=0.006), asthma control test (OR, 0.971; 0.905 to 0.999; p=0.046), CLT (OR, 1.007; 1.001 to 1.013; p=0.049) and α2-macroglobulin (OR, 0.938; 0.886 to 0.992; p=0.025) were all identified as independent predictors of exacerbated asthmatic events.
The most important factors that contribute to the risk of asthma exacerbation were severe asthma (relative risk [RR], 1.55; 1.19 to 2.03; p<0.0001), oral corticosteroids at baseline (RR, 2.15; 1.49 to 3.11; p<0.0001) and gastroesophageal reflux disease (RR, 2.5; 1.7 to 3.61; p<0.0001).